Fog eliminating apparatus for rock drills



March 28; 1939.. DICKENSQN 2,152,176

FOG ELIMINATING APPARATUS FOR ROCK DRILLS Filed Sept. 2, 1958 INVENTOR Ema esiflflickenson HIS ATTORNEY BYS Patented Mar. 28, 1939 UNITED STATES PATENT OFFICE FOG ELIMINATING APPARATUS FOR ROCK DRILLS Application September 2, 1938, Serial No. 228,141

5 Claims.

This invention relates to pneumatic rock drills and more particularly to apparatus for eliminating exhaust fog and dust produced thereby.

In the operation of rock drills of the pneumatic type it has been found that the more efficiently the compressed air is utilized, the lower will be the temperature of the exhaust air issuing therefrom. This is naturally to be expected inasmuch as the heat extracted from the air represents part of the work done by the drill. In installations using long compressed air pipe lines, the heat of compression from the source is dissipated by radiation so that the air entering the rock drill is likely to be at close to atmospheric temperature. Under such circumstances, in a fairly efiicient drill, the exhaust air temperature drops to a point well below zero Fahrenheit. The effect of introducing large quantities of extremely cold air in a moisture laden atmosphere, such as ordinarily exists in mines or tunnels, where ventilation is necessarily somewhat limited, is to produce a fog which in many cases is considered a hazard. The fog-producing tendency of the exhaust air can be very materially reduced by raising the temperature of the exhaust air. The fog produced is not particularly dangerous when this temperature is not lower than ten degrees Fahrenheit.

A number of methods have been suggested for raising the temperature of the exhaust air, as for instance, preheating the air as it enters the rock drill. In this instance, however, it is preferred to heat the exhaust by mixing it with warmer air prior to releasing it in the atmosphere.

It is accordingly an object of this invention to provide apparatus for heating the exhaust air from a rock drill by combining it with warmer air upon its discharge from the drill.

Another object of the invention is to cause the exhaust air from the drill to operate as an ejector to automatically entrain relatively warm atmospheric air for heating the exhaust.

Still another object of the invention is to concentrate the withdrawal of air from the atmosphere near the point of drilling so as to, in a large degree, eliminate dust caused thereby and in the vicinity of the drill.

Other objects and advantages will become apparent from the following description of a preferred embodiment of the invention in which similar reference characters refer to similar parts, and in which,

Figure 1 is a side elevation of a drill embodying the invention,

Figure 2 is a cross section taken along the plane 22 looking in the direction of the arrows Fig. 1,

Figure 3 is a cross section taken along the plane 33 of Fig. 1, looking in the direction of the arrows, and

Figure 4 is a View of a portion of the drill partly in section, through the exhaust port and the air mixing and conducting chamber.

Referring to the drawing, a drill I0 is mounted upon cylindrical guide members [2 and adapted to ride longitudinally thereon as its drill steel [4 penetrates a bed of rock [6. For this purpose the drill is provided with brackets [8 attached to the drill body by side rods 20. Suitable bearings 22 in the form of rings, are removably attached to the brackets by set screws 24. These rings encircling the cylindrical guides [2 are, therefore, removable and replaceable when worn,

The rear end of the drill has attached to its back head 26 a stem 28 extending to yoke 30 and bolted thereto by a nut 32. Yoke 30 is attached by nuts 34 to piston rods 36 having pistons 38 (Fig. 1) working in the guide cylinders 12 and adapted by suitable pressure on the ends thereof to feed the drill l0 backward and forwardly with respect to the guide cylinders 12.

The operation of the feeding mechanism of which pistons 38 are a part, is not described in detail herein inasmuch as it is not part of this 30 invention. It is understood that any desirable feed mechanism for the drill l0 may be employed.

Guide cylinders 12 are attached together by yokes 40 and 42 which, in turn, are welded to a base 44 provided with a cone 46 for engagement with a cone clamp 48 of a conventional and wellknown design. 1

Yoke 42, as shown in Fig. 3, also has a pair of ring shaped removable bearings 50 encircling the guide members I2 and attached to the yoke by set screws 52.

As shown in Figures 2 and 3, yokes 40 and 42 are U shaped and with the base (44) provide a space for an air conducting member or passage 54 extending the length of the guide members [2. The passage 54 is formed by upright plates 56 and 58 welded at their lower edges to base plate 44 and bent in at 60 and 62 toward each other. Upon the bent-in portions 60 and '62 are mounted strips 64 of suitable flexible material, such as rubber, and slightly stiff so as to press rather firmly together at their edges. The strips 64 are held in position by metallic strips 66 riveted to the bent-in portions 60 and 62.

Drill I0 may be of any suitable design. In this instance, the exhaust port 68 is of the well-known piston controlled variety and is provided with a passage 69, leading through the cylinder wall to convey the exhaust air from the cylinder to a nozzle 10 suitably attached to the drill exterior. Nozzle 10 is positioned on the lower side of drill l0 so as to extend between flexible flaps 64 which form a seal about the nozzle. This seal does not, in this instance, need to be particularly tight.

The passageway 54 is open at 12 adjacent the front end of the drill and the nozzle ID is preferably directed away from this end to produce an injector action in the passageway to draw air from around the front end of the drill toward the rear. Passageway 54 is provided at the rear end of the base plate 44 with an outlet 14 preferably formed integrally with base plate 44 and is arranged to receive a suitable hose 15. The rear end of the passageway 54 is blocked oif at 16 so as to direct the exhaust and entrained air into the hose 15.

In operation, the exhaust discharged from the nozzle 10 is adapted to entrain air in the passageway 54 with which the very cold exhaust air mixes as it passes through the passageway 54. Some heat is also absorbed from the walls of the passageway 54 and the warm mixture passes from passageway 54 into the outlet 12 and hose 15 to a point sufiiciently distant to avoid any tendency of fogging in the vicinity of the drill operator.

As is customary in most underground operations, ventilation is required to dilute the contaminated air at the face of the working for the purpose of removing health hazards to the operator. Therefore, the hose 15, as said before, should be suiiiciently long to carry back to a point where ventilation is sufiicient to carry away and dilute the contaminated discharge therefrom.

In this instance, the location of the air inlet to the passageway 54 is located adjacent the source of dust, so that a large part of the dust caused by drilling the rock [6 will be carried out in this way.

It will be noted that as the drill ill rides forward and back on its guide, the flexible strips conform generally to theshape of the nozzle and fold themselves about it so as to form a continuous passage with no substantial leaks throughout the length of the passageway. The strips 64 are also sufliciently stiff to withstand the slight air pressure within the passageway 54 without spreading at their abutting edges.

Thus, by the above construction, are accomplished among others, the objects hereinbefore referred to.

It is understood that modifications of the structure above described will occur to those skilled in the art without departing from the spirit of the invention, and that such changes are intended to be included within the scope of the appended claims.

I claim:

1. In apparatus of the type described, a pneumatically operated rock drill having an exhaust passage and an exhaust conducting nozzle associated therewith, guide means for said rook drill to permit axial movement of said drill, an

exhaust receiving member extending lengthwise of said guide means and stationary with respect thereto, adapted to receive said nozzle and having an opening to atmosphere adjacent the forward end of the guide means, and sealing means on said receiving member and about said nozzle to concentrate the inflow of air to said opening and said nozzle.

2. In apparatus of the type described, a pneumatically operated rock drill having an exhaust passage and an exhaust conducting nozzle mounted thereon and movable therewith, guide means for said rock drill to permit axial movement of said drill, an exhaust receiving member extending lengthwise of said guide means and stationary with respect thereto, adapted to receive said nozzle and having an opening to atmosphere adjacent the forward end of the guide means, and sealing means on said receiving member and about said nozzle to concentrate the inflow of air to said opening and said nozzle.

3. In apparatus of the type described, a pneumatically operated rock drill having an exhaust passage and an exhaust conducting nozzle mounted thereon and movable therewith, guide means for said rock drill to permit axial movement of said drill, an exhaust receiving member extending lengthwise of said guide means and stationary with respect thereto, adapted to receive said nozzle and having an opening to atmosphere adjacent the forward end of said guide means, sealing means on said receiving member and about said nozzle to concentrate the inflow of air to said opening and said nozzle, and means to convey air from said receiving member to a point remote from the drill.

l. In apparatus of the type described, a pneumaticaly operated rock drill having an exhaust passage and an exhaust conducting nozzle mounted thereon and movable therewith, a pair of guides for said drill disposed on either side thereof to permit axial movement of the drill, an exhaust receiving member extending lengthwise between said guides and stationary with respect thereto and adapted to receive said nozzle, said member having an opening to atmosphere adjacent the forward end of said guides, and sealing means on said receiving member and about said nozzle to concentrate the inflow of air to said opening and said nozzle.

5. In apparatus of the type described, a pneumatically operated rook drill having an exhaust passage and an exhaust conducting nozzle mounted thereon and movable therewith, a pair of guides disposed on either side of the drill and arranged to permit axial movement of said drill,

an exhaust receiving member extending lengthwise of and disposed between said guides and sta tionary with respect thereto, said member being adapted to receive said nozzle and having an opening to atmosphere adjacent the forward end of the guides, and sealing means on said receiving member and about said .nozzle to concentrate the inflow of air to said opening and said nozzle, including a pair of flexible members forming one side of said receiving member and normally having abutting edges adapted to be displaced by said nozzle.

ERNEST H. DICKENSON. 

